JSFiddle - React, Tailwind, and code Playground

JavaScript

window.addEventListener('storage', storageEventHandler, false);

function storageEventHandler(evt){
    alert("storage event called key: " + evt.key );
    switch(evt.key){
        case 'bat1':
        case 'bat2': batteryDCMeter(); break;
        case 'extPowerOn': rechargeBattery(); break;
    }   
}

sessionStorage.setItem("someKey", "someValue");